This has probably already been discussed - but with the conqueror going though this 4x3 419mm redesign (which fortunately seems to be REALLY unpopular) - I propose WG just give us the N3 - 9 18" guns, in a layout which will be totally unique to any other BB of any other line
It's so British - somewhat impractical but still very impressive - DO IT WG, DO IIIIIIIIIT

Armour on the Nelson is good, just because the belt is somewhat narrow doesn't mean the rest of the armour doesn't exist.
Nelson's unconventional turret layout is actually VERY interesting, it means you can always zig-zag towards the enemy and keep firing, take Izumo - it has the rear-most turret facing backwards so turning the ship means that turret has to turn over 180* every time, Nelson this does not happen, so you can continue to fire all 9 guns while being a smaller target to hit in a zig-zag of death
People often bring up that the 16 inch guns weren't particularly that much greater than the 15 inch guns etc. but they forget this is a game - bigger calibre means more potential damage simple as that, range is usually fairly accurate in WoWS so that is an argument that can be had but Nelson (as I said mentioned) has tricks up its sleeve with big guns and more armour, tier VIII maybe but not tier VII (unless you want it to be OP)
N3 has as many 18 inch guns as Yamato with armour as thick as the L3 - I don't believe it can be tier IX, either tier X or not at all

Nelson has substantially thicker armour just about everywhere (apart from colorado has thicker turret faces) - and its unconventional layout is actually VERY interesting, it means you can always zig-zag towards the enemy and keep firing, take Izumo - it has the rear-most turret facing backwards so turning the ship means that turret has to turn over 180* every time, Nelson this does not happen, so you can continue to fire all 9 guns while being a smaller target to hit in a zig-zag of death
Nelson also supposedly for the most part has armour as thick as Iowa (apart from Iowas turrets are MUCH thicker), Iowa does of course have mighty AA capability but I am confident Nelson would be competitive, especially against Izumo.... You can make an argument for Nelson to be tier VIII but tier VII is laughable
People often bring up that the 16 inch guns weren't particularly that much greater than the 15 inch guns etc. but they forget this is a game - bigger calibre means more potential damage simple as that, range is usually fairly accurate in WoWS so that is an argument that can be had but Nelson (as I said in the first half of this double-reply) has tricks up its sleeve with big guns and more armour
N3 has the same armour as L3 so they both have less armour than the Yamato, and both are not as fast too - the only argument is the gun placement - meaning N3 is OP at tier IX, either have it at tier X or not at all

Oh don't worry I know Edgar is OP for tier I - however, what you forget is: Edgar is an epic name
May I ask why armoured cruisers are a no-go? I don't know what WG has said about them
My reasoning for Crown colony being higher is simply because they're basically the same statistically however Crown Colony is slightly smaller (harder target) and also designed later, when 2 things are pretty much the same but one is designed later I figures just give it more health and perhaps better handling it'll be worthy of outclassing the Town class
My issue with C-Class is it only has 2 guns ('primary' I mean) which even at like tier II or III is bad... D-Class could go somewhere but what I've done is just 1 imagining Britain had lots of cruisers between WW1 & WW2
Do you think county could go tier VIII (replacing York) and Edinburgh could go tier IX? Edinburgh has more (but smaller) guns and better AA armament - SLIGHTLY better speed too?
My 'battlecruiser' line (probably just called BB in the game) would be balanced in other ways - remember they have smaller guns than normal BBs, faster speed, but with less armour - then stats that are completely up to WG like health (and to an extent reloads) can be changed to make them not simply destroy other same-tier BBs
Iron Duke has 10x13.5" guns Arkansas will have 12x12" guns, Iron Duke has more armour but Arkansas has much better AA capability - I'd say that's fair.
KGV has too small guns with too little armour (apart from its pretty decent main belt) to be tier VIII when there's vanguard there
HOW the Hell is Nelson tier VII? 9x16" guns in excellent positions with lots of armour - I would EASILY pick Nelson over KGV - Vanguard chooses speed over armour so you could possibly swap them around but Nelson tier VII? Don't make me laugh!
How can N3 be tier IX? a tier IX with 9 18" guns? I can understand you wanting L3 to be tier X instead but N3 at tier IX would be excessively OP. You saw my reasons for choosing N3 over L3 they're menial but that's just what I chose
Like I said, DDs are my weakest point - you say they're a complete mess now when I first started drawing this up it was MUCH worse

I ASSUME The British cruiser line will look something along the lines of: 1- Edgar
2- Chatham
3- Challenger
4- Monmouth
5- Leander
6- Town (Belfast as tier VI premium)
7- Crown Colony
8- York
9- County
10-Minotaur
Of course there are lots of light cruisers to pick from tier 1-4 but tier 5 onwards I think will be as I have listed

I have posted a Royal Navy tech tree similar to this on the forums before, but I have updated it so the DD line is much better, CV line somewhat fixed, I still defend the BB line, and CAs have a hopefully worthy tier X now
Just to note on the BBs (I saw people debating tier X L3 vs N3 etc. aswell as the entire final few tiers of the tree, I agree for the most part with ChaplainDMK, you want a gradual increase in calibre and armour not randomly hopping about - that is why KGV is tier VII for me, smaller guns than Nagato but more of them, Vanguard is tier VIII because slightly less armour than Nelson aswell as its higher speed closer to KGV it'd be annoying to go from 28 knots to 24 back up to 30 then down again for N3 The reason I chose N3 over L3 is because they are basically the same but L3 will be basically a Yamato with a different flag, whereas N3 will at least be different and still statistically the same as N3 it just cant shoot directly backwards (hey, Izumo can't and that's hardly crap!)
My aircraft carrier line may not be 10/10, USS Midway still outclasses Audacious but I simply cant find a better British Carrier that wasn't designed for jets! Perhaps they can do as they did with the Japanese line and tinker with squadron size etc.
I'm happy with my Battleship and Battlecruiser line (If they ever do introduce a battlecruiser line in the future, which I think is possible just like the germans have 2 heavy tank lines in World of Tanks) aswell as my Cruiser line, not 100% confident with destroyers but it seems to be alright xD

I ASSUME The British cruiser line will look something along the lines of: 1- Edgar
2- Chatham
3- Challenger
4- Monmouth
5- Leander
6- Town (Belfast as tier VI premium)
7- Crown Colony
8- York
9- County
10-Minotaur
Of course there are lots of light cruisers to pick from tier 1-4 but tier 5 onwards I think will be as I have listed

Very comprehensive, I made this just yesterday before stumbling upon yours now, I'll give you the aircraft carrier tree I know little about them, even less about Destroyers so yours may well be superior in that aspect too However I disagree with your Battleship Tree somewhat it appears, I think you're severely underestimating the Nelson-Class capability - and I had different plans for the Lion.... but at least we agree on having a separate battlecruiser line XD The Royal Navy had many cruisers to try juggle into a tree so I see why we've come up differently - I'd argue neither are technically superior, they're just 2 different lines WG could take But, as well all know, Lord Clive is best ship RN